The use of semiconductor wafer/substrate material handling units in industry is known in the prior art. For instance, U.S. Pat. No. 4,722,298 (R. Rubin et al.--Feb. 2, 1988) discloses a self contained modular processing device for semiconductor wafers comprising a chassis with an integral processing module adapted to perform at least one function, i.e. coating or baking etc. The Rubin et al. patent discloses a "building block" concept with "plug in" modular processing to accomplish a multi-functioning system capable of handling a silicon wafer in multiple directions, including "parallel or branch" tracks. Rubin et al. teaches a modular processing apparatus comprised of one or two chassis about which are attached modules. The patent further teaches the integration of a CPU for controlling the processing of the workpiece. The Rubin, et al., patent further describes the modules as standard industry modules known in the industry. Similarly, U.S. Pat. No. 4,851,101 (M. Hutchinson--Jul. 25, 1989) discloses a sputter coating module for a multifunction device comprising a chamber means capable of holding a vacuum and also has a port to accept a wafer for processing. The Hutchinson device has a means for rotatable wafer support as well as a means to sputter coat the wafer and the disclosure teaches and claims a coating module which utilizes vacuum and gas port systems to perform the sputter deposition.
U.S. Pat. No. 4,801,241 (J. Zajac, et al.--Jan. 31, 1989) discloses another modular article processing machine for semiconductor wafers and method of article handling comprising the steps of transferring articles simultaneously from location to location until all modular chambers contain unprocessed articles and then simultaneously processing the articles until all articles are placed in an output chamber having completed the processing. Zajac et al. also teaches an additional method wherein there is at least two processing stations. Like Zajac, et al., U.S. Pat. No. 4,825,808 (N. Takahashi, et al.--May 2, 1989) discloses a substrate processing device comprising "modular" input and output chambers wherein substrates may be loaded and unloaded for purposes of processing.
U.S. Pat. No. 4,917,556 (L. Stark et al.--Apr. 17, 1990) discloses still another modular semiconductor wafer processing machine comprising interconnected handling units, each with wafer handling arms which are in turn capable of passing a wafer to another unit in a vacuum environment through ports which are opened and closed by valve means. This invention discloses a gate means to isolate material handling units for purposes of processing workpieces. Then in U.S. Pat. No. 5,474,410 (M. Ozawa, et al.--Dec. 12, 1995) it discloses a multi-chambered processing unit with cassette carrier comprising cassette chambers into and out of which a plurality of substrate cassettes are carried under pressure and a series of load lock chambers between which the substrates may be carried and the substrate is also carried within a series of vacuum process chambers. This patent discloses cassette chambers which are small in size which prevents the substrates from coming out of the cassette when the cassette is carried into and out of the chambers and which also do not interfere with components functioning.
The aforementioned prior art of semiconductor wafer/substrate material handling units generally involve lengthy, labor intensive and error prone assembly of processing units to a material handling unit which do not permit portable modularity, clustering and multi-tasking. For instance, U.S. Pat. No. 5,733,024 (A. Slocum, et al.--Mar. 31, 1998) discloses a modular system with a plurality of mounted modules at pre-determined locations by means of kinematic couplings comprising a rigid frame to which a plurality of modules are attached by kinematic couplings such that the frame forms a common substrate with the module defining a global set of reference axes which are set in a pre-determined relationship with each type of module. These couplings utilize three aligning element pairs which serve to define six contact surfaces. This prior art also involves a lengthy, error prone manual adjustment to accommodate the handling of different size and shape wafers. The application of such art is primarily in the processing of semiconductors where photoresist polymer coatings are applied and bonded to wafers of various sizes and shapes. These applications are limited, however, since they are generally unable to allow for material handling units to be portably clustered and connected to portable self aligning process modules. Also in U.S. Pat. No. 5,076,205 (E. J. Vowles, et al.--Dec. 31, 1991) it discloses a multichamber system for processing of semiconductor wafers comprising a portable processing chamber assembly which is matable with a stationary multi-processing station which incorporates a means for releasably docking a mobile housing with a stationary multi-processing station.
These prior art applications also do not provide for interfacing of portable process modules that are automatically recognized by the material handling unit central processor. The prior art generally requires a lengthy manual procedure of attaching a process unit or module to a material handling unit which is not self-aligning and not self-sealing. The prior art also does not provide for the automatic detection and alignment of the semiconductor wafer/substrate cassette station requiring that a manual adjustment be made when a different size or shape of wafer is introduced to the system for processing.
The prior art also does not disclose a semiconductor wafer/substrate material handling unit with a thermal processing chamber which utilizes compact, sturdy, chemical and temperature resistant lift pins which are integrally connected to the door mechanism, and are both engaged by one motor action. U.S. Pat. No. 5,484,483 (M. Kyogoku--Jan. 16, 1996) discloses a thermal treatment device for semiconductor materials designed to prevent metal contamination, maintaining a sealed and isolated environment between the wafer transfer system and thermal chamber despite pressure differences between the chambers. The workpiece in Kyogoku is placed in the thermal treatment chamber by moving a boat supporting workpieces and does not disclose a support or lift pin configuration as is disclosed in the present invention. The Kyogoku patent teaches atmospherically isolated thermal processing units which are engineered to prevent metal contamination of the workpiece. Unlike the present invention the prior art utilizes lifting mechanisms with relatively high thermal conductivity and substantial surface area contact with the wafer being coated which can thermally affect the resist coating of the wafer in an adverse manner.
The prior art is also bulky in size and take up as much as sixty-six percent (66%) more floor space than the invention disclosed herein. As such, the basic concept of automatic module and cassette station detecting and aligning semiconductor wafer/substrate material handling unit with a thermal processing chamber module having an integrated, sturdy, chemical and temperature resistant wafer lift pins and door actuation apparatuses and their use are disclosed.
While the prior art discloses semiconductor wafer/substrate material handling unit apparatuses which fulfill their respective particular objectives and requirements, and are most likely quite functional for their intended purposes, it will be noticed that none of the prior art cited disclose a device that allow for the clustering of material handling units which further easily and automatically self-align and seal-seal precisely in place for operation, several differing process modules, or any combination of modules thereof, which are automatically recognized and controlled by the material handling unit's central processor. Further, the prior art does not utilize automatic alignment and detection of semiconductor wafer/substrate cassette stations. In particular U.S. Pat. No. 5,246,218 (H. Yap et al.--Sep. 21, 1993) discloses a device for securing an automatically loaded wafer cassette on a processing device platform comprising two guiding means which are further comprised of base bars and front and side walls which automatically and precisely align the wafer cassette once the two guiding means have received the cassette upon manual placement, however, this patent's securing means does not teach or claim automatic cassette or wafer size detection as the present invention.
Also, none of the prior art utilizes a thermal processing chamber with sturdy, chemical and temperature lift pins which actuate integrally with the thermal processing chamber door with one motor in a manner which minimizes the lifting mechanisms thermal impact upon a wafer being processed in the chamber. As such, there apparently still exists the need for new and improved semiconductor wafer/substrate material handling unit with a thermal processing chamber apparatuses which can be operated without extensive manual adjustment by providing for self-aligning and self-sealing portable modules that are automatically recognized by the central processing unit of the material handling unit and utilize thermal processing chambers which lift the wafers being processed with sturdy, chemical and temperature resistant lift pins that are integrally actuated with the door mechanism by a single motor action and further automatically detects and aligns to accommodate differing wafer sizes and shapes present in the cassette station. In this respect, the present invention disclosed herein substantially fulfills this need.